Sandalwood (Santalum album) is a slow-growing hemi-parasitic tropical tree of great economic value found growing in southern India, Sri Lanka, eastern Indonesia and northern Australia. The timber is highly sought after for its fine grain, high density and excellent carving properties. Sandalwood heartwood has a unique fragrance imparted by the resins and essential oils, including santalols, santalenes and other sesquiterpenoids, in the heartwood. In general, Santalum album heartwood contains up to 6% dry weight sesquiterpene oils. Sandalwood oil predominantly contains the sesquiterpene alcohols α-santalol, β-santalol, Z-α-trans-bergamotol and epi-β-santalol, and additionally includes α-santalene, β-santalene, α-bergamotene, epi-β-santalene, β-bisabolene, α-curcumene, β-curcumene and γ-curcumene. Sandalwood oil has a soft, sweet-woody and animal-balsamic odor that is imparted from the terpenoid β-santalol and is highly valued. Sandalwood oil has been obtained by distillation of the heartwood of Santalum species and is used as a perfume ingredient, in incenses and traditional medicine and in pesticides.
Centuries of over-exploitation has led to the demise of sandalwood in natural stands. Large plantations are being established throughout northern Australia to satisfy demand and conserve remaining reserves. In addition, there is great variation in the amount of heartwood oil produced, even under near-identical growing conditions, due to genetic and environmental factors, such as climate and local conditions. Generally, the price and availability of plant natural extracts depend upon the abundance, oil yield and geographical origins of the plants.
Although chemical approaches to generate santalols and the other sesquiterpenoids in sandalwood oil have been attempted, the highly complex structures of these compounds have rendered economically viable synthetic processes for their preparation in large quantities unattainable. Thus, there is a need for efficient, cost-effective syntheses of santalols and other sesquiterpenoids that impart the highly sought after sandalwood fragrance for use in the fragrance industry.
Thus, among the objects herein, is the provision of methods for the production of santalols and other sesquiterpenoids and the resulting products of the methods.